Hydraulic remote-control system



J. W. KELLY HYDRAULIC REMOTE CGNTROL SYSTEM March 26, 1946..

FiledFeb. 26, 1944 2 sheets-sheet i1 March'26, 1946. J. w. KELLYl 2,397,270

- HYDRAULIC REMOTE CONTROL SYSTEM I maar. ze, 1944 2 sheets-sheet 2 Patented Mar. 26,1946 I uNi'nazD STAT;

California s. PATENT; OFFICE zsirnzw nrnnamo nEMo'r-E-cou'rnoi. sr

John W. Kelly,l La Canada, C Y Precision Products Corp.,

STEM

alif.,assignortoAdei a corporation of Application February 2s, 1944, serial No. 524,113

.sexism (creo-54.6)

This invention relates to hydraulic remote con-- trol systems, particularly the closed, manually operated type for operating aircraft engine throttles, other aircraft controls and various other devices and mechanisms subject to operation and control by such a system.

My pending application for United States Letters Patent Serial No. 475,301, led February 9, 194.#3, for Hydraulic system exemplifies asystem similar to that of thel present invention. However, the present invention, while h aving desirable characteristics of my former system, embodies certainlimprovements over it and other systems heretofore used, .such as the provision for pronounced reliability of performance, Ireduction of weight, size, bulk, number or parts, and amount of material, the elimination of poppet pliflcation of construction, and the provision of a novel hydraulic lock 'and thermal relief 'valve combination in the receiver or motor unit. 'Ihis l combination of locking and relief valves likewise with such other obiects and advantages as may subsequently appear, the invention resides in the parts and in the combination, construction and arrangement of parts hereinafter described and claimed, and illustrated by way of example in theaccompanying drawings, in which:

Fig, 1 is a semi-schematic view. of a system embodying the present invention, showing the transvalves in the master or transmitter unit, simembodying my invention, includes a motor o r rereduces weight, bulk, size and Amachining and other production costswhile also making the system fully and accurately responsive at all tixes regardlessv of thermal changes and minor.

leakage, byA reason or the emcient manner in which said combination responds to thermal changes and fluid displacement in cooperation with the master unit and a particular pressurized equalizing device or accinnulator. Thisequaliser provides sources of supply of tluid under pressure connected to the dual fluid lines of the system to initially pressurize the system and maintain it pressurized and equalized4 under variable .thermal and operating conditions.y

One of the objects of the present invention is to provide an improved receiver or motor unit tor hydraulic remote control systems, whichv unit embodies a build .-in.' coaxial valve combination including two hydraulic lockivalvesserving also as relief valves incident to 'contraction of the fluid, and two expansion relief valves embodied in the llocking valvesin 'a novel manner toconserv'space, reducemachiningI costs, and render the unit as va whole more eiilcient and reliable.

' an operating means F for the unit C. and a presthe equalizer taken Referring to the drawings more specifically it is seen that a hydraulic remote control system,

ceiver unit A, a drive vor transmission means B operated thereby to actuate an airplane engine throttle or other control or device, not shown, a manually operable master or transmitter unit C, dual iluid lines D and E operatively connecting the transmitter and receiver umts to one another,

surized equalizer unit G connected to the lines D and E for thermal and other compensation and equalizing purposes in' cooperation with a hydraulic lock and relief valve combination H embodied. in the motoror receiver-unit A, whereby the per volume of nuid is maintained throughout the system under variable temperatures and minor leaks.

As here provided the master or transmitter lunit C includesV a cylinder l in which a piston Another object o! 'my invention is to provide for a system such as described animproved equal-k izer of simple, iight weight and comparatively inexpensive constructionailording a most reliable izedinahighlyemcaciousmanner.

with the formino chicas inevieiw.

Hedualizing action and` initially pressurizing the Y' systemandmaintainingitpressurizedandequallable nttings I.

2 is reciprocable for transmitting operating iiuid under pressure from either or the ports 3 and l through either of the lines D and E which iatter are connected to said ports by means of suit- The operating means? for the master unit C .includes a lever l pivoted at 1 on a bracket! and connectedbycanoi.' alinklwiththepiston'rod Il whereby the piston-2 may be' selectively opcreteilto direct operating fluid throush either of thc'linol D and E. l

AAsynchronizing;possess il is tcrmed'in the wail ofthe cylinderhi to by-fpas's i'iuid around the piston l and is controlledby means or v.a manually operated valve il which may also' be 'us'edasa bl'ced'velvetoremcve trapped'air from theoylinder and system' section thereof shown in radial ports 35 -open to these I3 in which a piston I4 is reciprocable responsive to pressure fluidentering the ends of the cylinder through the ports I5 and I6, with which ports the lines D and E are afforded communication through a bore I1 in the wall of the cylinder I3, and'ports I8 and I9. 'I'he ports I8 and I9 lead into ttings and 2I to which the lines D and E are connected. The ports I8 and I9, the cylinder bore, I1 and the ports I5 and I6 form fluid passages through which fluid passes to and from v A synchronizing passage and valve 25 therein are provided for the cylinder I3 in the same manner and for the same purpose as the passage II and valve I2 associated with the cylinder I- of the master unit.

In accordance with this invention the liow oi fluid to and from the cylinder I3 is controlled by check` valves 26 and 21 mounted in the end portions of the bore I1 and these valves also serve to hydraulically lock the motor unit. The valve 26 is positioned between the port I5 andport I8 while the valve 21 is disposed between ports I6 and I9, whereby the flow of fluid to and from the line D and the left end of the cylinder, as shown in Fig. 1, is controlled by valve 26, and the flow through line E to and from the right-,end of the cylinder is controlled by valve 21.

Each of the valves '26 and 21 is tubular and has a conical end 28 adapted to seat on a seat 29 formed interiorly of one end of a cylindrical valve cage 30 in which the valve is reciprocable. The cageis fitted in a. counterbore 3| in the bore I1 and is sealed at its ends by the sealing rings 32.

The motor or receiver unit A includes a cylinder Springs 33 seated in recesses 34 in the Vvalves 26 and 21 and bearing against the end walls of the bore I1 urge the valves against their respective seats. When the valves 26 and 21 are opened.

iiuid will flow through radial ports 35 in the cages 30 it being noted that the cages are provided with peripheral grooves 35' in registration with the grooves as shown in Fig. 5.

As a means for automatically controlling the check valves 26 and 21 a valve actuating piston 36 is arranged to reciprocate in the bore I1 be-v tweenthe-valves so that stem members 31 and 38 extending from opposite ends of the piston Will engage and open the valves. Springs 39 normally hold the valve actuating piston centered with the stem members somewhat spaced from vthe valve 26 and 21 as shown in Fig. 1. When pressure uid the valve 26 will be opened responsive to the pressure of such fluid and the motor piston I4 will be moved to the right (see Fig. 1). At the same time that valve 26 is unseated by the fluid, the piston 36 is moved to the right -wherebythe stem.V 38 thereon will extend through the adjacent end of the cage 30 and engage and unseat the valve 21. Valve 21 now acts as a. return valve to allow fluid to return from the right end of cylinder I into line E and thence to the master or transmitter unit cylinder I.

When the pressure iiuid is transmitted through line E the piston 36 moves to the left, valve 21 is l opened by uid pressure and valve 26 is opened (i0 enters the bore I1 from line D through port I8""i .motor unit A andoperates the valves 26 and; 21

therein as hereinbefore notedvto cause the piston to move to the right. Opposite movement of the master unit pistoni will cause the opposite valve action hereinbefore described as well as movement of the motor piston I 4 to the left.

A particular feature of my invention is the pro` vision of a novel thermal expansion relief valve means embodied in the check valves 26 and 21 themselves, which latter also serve as fluid contraction compensating valves as well as provide for hydraulically locking the motor piston `I4. This novel valve combination is provided for by means of ball check relief valves 40 and 4I in the valves 26 and 21 respectively, these ball checks being arranged in the relief passages 42 alorded by the tubular formation of the valves 26and 21. In the relief passages 42 are seats 43 against which the ball valves 40 and 4I are urged by the springs 44 and the pressure of the uid in the bore I1. Tubular keepers 45 hold the springs in the relief` passages 42 and are disposed so that their outer ends are adapted to be engaged by the stems 31 and 38 on the valve actuating piston 36 to unseat the valves 26 and 21. Excessive pressure due to thermal expansion of fluid in the motor cylinder' I3 will cause either of the relief valves 46 and 4I to open and permit of a compensating ow. into the system through the ports I5 and I6 past the body of either of valves 26 and 21 which havea and 4 l .17;

I may as here shown provide minute groovelike passages 46 in the bodies of the valves 20 y and 21 to afford communication of the relief passages 42 with the ends of the cylinder I3 when the valvesi26 and 21 var'e seated, whereby the ball relief valves 40 and 4I are subject to being` opened when excessive pressure is'caused by thermal expansion 0f the uid in the cylinderl.`

It is now seen that the valves 26 and 21 in having the check valves 46 and 4I embodied therein as herewith shown and described make for a small compact and highly eicient valve combination providing for hydraulic locking of the motor unit as well as for full thermal expansion and contraction compensation thereof The pressurized equalizer unit G` hereof includes a cylinder 50 having coaxial bores 5I and '52 of differing diameters whereby an annularshoulder A53 is defined between said bores. A wall 54 closes the lower end of this cylinder whereas a cover or lid 55 is mounted on lthe upper end of Athe cylinder by means of the fastenings 56.

Mounted in the equalizer cylinder 50isa dual piston 51 having a larger piston portion 58 operable in the larger bore 5I and a smaller integral Whereas a second uid compensating chamber L is provided in the bore 52 between the end of pisl ton portion 59 and the wall 54 of the cylinder. A

passage 6| extends through the wall of the cylinder 50 so that one endvopens through the shoulder 53 into the chambenK while the other end extends through the lower wall 54l and receives aaasmvo l iitting 62 by means of which a conduit 83 connectsthe equalizer with the fluid line E. A similar passage I4 extends through the wall of the cylinder 50 so as to intersect as at 6I the lower end of the chamberL and at its lower end receives a fitting 8l by means of which a conduit line B1 is connected to the equalizer to aiIord communication of the chamber L with the line D.

, one of the valvesand move the valve actuating A lieror uid intake passage 68 correspond- 10 valves arranged in said relief passages to open ing to passage I4 is provided in the wall of the cylinder 50 and opens in the bore 52 or chamber L. A check valve 69 is mounted in passage B8 so as to unseat on introducing iluid through said passage into the equalizer. A removable screw cap v1li closes the outer end of the filling' nipple and valve seat member 'Il which is mounted in the intake passage 68..

A bleeder passage 12 corresponding to the passage 8| is formed in the wall of the cylinder 50 and opens into the chamber K. A screw valve 13 is mounted in the lower end of the passage 12 to control said passage whereby air trapped in the equalizer may be bled therefrom.

Hydraulic uid is `charged into the ychambers K and L and the dual piston 51 is elevated ac- 25 cordingly following which air is introduced into the upperv part of the bore 5I :through a valved air intake 'Il until suflicient air pressure is reached to initially pressurize the system. The equalizer now becomes in effect a dual fluid reservoir with the fluid in the chambers K and L piston means to engage and open the other valve, said check valves having thermal expansion relief passages adording communication between said 1 bore ports and portions of said bore which are open yto said cylinder ports when said valves are closed,.and normally closed spring loaded relief responsive to thermal expansion of the iiuid in said' cylinder, tubular valve cages in said borev having said seats at certain ends thereof and in which said check valves are operable, and radial ports in said cages 4aiiording communication or said bore ports with said cylinder ports when said check valves are unseated.

2. In a hydraulic unit, a cylinder having a pair of operating passages for delivering fluid under 0, pressure to and discharging iiuid from the ends delivered ing iiuid, relief under pressure and in direct communication with the iluid in the lines E andD of the system so that in the event of thermal expansion and contraction of the i'luid in the cylinders of the units A and C and in the lines D and E, the equalizer will function to receive fluid from said lines or cause iiuid to be discharged into the'lines whereby the requisite volume of fluid is maintained throughout thev system at all times. When ther- 4o vim; passages mal expansion takes place in the lines D and E, f

and associated units. the increased pressure raises the dual piston in the equalizer so that the capacity of the chambers K and L is increased to accommodate the expanded duid and thereby relieve the excess pressure in the system. Upon contraction of the4 duid the air pressure in the equaliser forces vthe vdual piston downward causing a compensating discharge of duid into the system lines D and E. v

While I haveshown and 'described a speciiie embodiment of my invention I do'not limit myself to the exact details of construction set forth. and the invention embraces such changes, modincations and `equivalents of the parte and their formation and arrangement as come within the purview of the appended claims.

I claim:

' 1. In a hydraulic motor unit, a cylinder having a cylindrical bore in a wall thereof. cylinder ports 50 bore aiiording communication between end portions of said cylinder endend portions of.said bore; bore ports adording commimicstion of said bore at points'between said cylinder ports with the duid linesoiahydraulicsystem.amotorpistoninsaid cylinder, valve seats in said bore between'the cylmeer ports-and the bore-ports. spring loaded checkvalvesmountedin ssid-boreto seat in a' direction toward lsaid bore ports so that when both valves are closed the motor piston will he hydraulically locked against movement, a valve actuatingplstonmesnshavinlaworkingiitin said bore between said bore ports and movable into positions for angelina and. opening said valves, spring means normally holdinssaidpistonmesnsilhsvingsaid of the cylinder, normally closed check valves arranged in said passages to open .responsive to pressure or operating fluid being transmitted to the cylinder and to close responsive tovpressure of duid passing from said cylindenvalve opening means responding to the pressure oi operating iiuid -in either of said passages to open one of the valves in the other passage while the valve in the passage into which the operating iluid is is opened by the pressure of the operatpass'ages in said check valves for by-passing iiuid from said cylinder around4 said 'valves when the latter are closed, spring loaded check valves normally closing said relief passages, and opening responsive to pressure in the 1 cylinder created by thermal expansion of .the iluid therein, while said check valves are closed. said relief passages extending axially through said check valves, cages moimted in said operatand enclosing said valves, valve means sealing said cages around their ends, and ports in said cages afici-ding fiowlof iiuid therethrough and into said operating passages when said check valves are seats on said cases,

Vunseated. Y 3. In a hydraulic motorvunit, a cylinder having a cylindrical bore in a wall thereof, cylinder ports affording. communication between end portions ot said cylinder and end portions of said bore;

,at points between said cylinder ports with the iluid lines of a hydraulic system. a motor piston in said cylinder, valve seats in said bore between the cylinder ports and the bore ports, spring loaded check valves mountedin said bore to seat in a direction toward said bore ports so thatwhen both valves are closed the motor piston will be hydraulically locked against movement, Aa. valve actuating piston means having a working nt in 'so said bore between said 'bore ports and movable A into positions for engaging and opening -said valves, spring means normally holding said piston means in a position-relative to said bore ports so that 'pressure fluid entering either bore. port will -y es open one ot the valves and move the valve actuat-v ingpistonmeanstoengage andopentheother valve, said' check valves having thermal expansion relief passages adording communication hel tween-said bore ports and portions of said bore v'I0 which are' open to said cylinder ports when said valvesare closed,.normally closed spring loaded reliefvalvesarrangedinseidreliefpsssagesto openresponsivetothermalexpansicnoftheiiuid in said cylinder, tubular valve cages in said bore Ports adording communication ot said bore sstseteertsinendstnmoraneinwhich said check valves are operable, radial ports.

in said cages affording communication of said bore ports with said cylinder ports when said check valves are unseated,and a tubular cage for the rst named valve mounted in said bore and having the valve seat for the first named Valve provided internally thereof, said cage having a port therein affording communication of the second port with said bore.

4. In a hydraulic motor unit, a cylinder having Aa cylindrical bore in a Wall thereof, cylinder portsi aifording communication between end portions of ysaid cylinder and. end portions of said bore; bore ports affording communication of said bore at points between said cylinder ports with the fluid lines of a hydraulic system, a motor piston in said cylinder, valvel seats in said bore between vthe cylinder ports and the bore ports, spring said cylinder ports when said check valves are unseated.

5. In a hydraulic motor unit, a cylinder having H a cylindrical bore in a wall thereof, cylinder ports said bore ports to operate said check valves so loaded check valves mounted in said bore to seat Y in a direction toward said bore ports so that when both valves are closed the motor piston will be hydraulically locked against movement, fluid pressure operable means in said bore between said bore ports to operate said check valves so that pressure fluid entering either bore port will act upon and open one of the Valves and will at the same time act upon said means and thereby open the other valve, said check Valves having thermal expansion relief passages affording communicav tion between said bore ports and portions of said bore which are open to said cylinder ports when said valves are closed, normally closed spring loaded relief valves arranged in said relief passages to open responsive -to thermal expansion of the fluid in said cylinder, and tubular valve cages in said bore having saidseatsat certain ends thereof and in which said check valves are operable, there being radial ports in said cages affording communication of said bore ports with that pressure fluid entering either bore port will act upon and open one of the valves and will at the same time act upon said means and thereby v open the other valve, said checkv valves having thermal expansion relief passages affording communication between said bore ports and portions of vsaid borev which are open to said cylinder ports when said valves are closed, normally closed spring loaded' relief valves arranged in said relief passages to open responsive to thermal expansion of the fluid in said cylinder, tubular valve' cages in said bore having said seats at certain ends thereof and in which said 'check valves are operable, there being radial ports in said cages aifording communi-cation of said bore ports with said cylinder ports when said check valves are unseated, and a tubular cage for the rst named valve mounted in said bore and having the valve seat for the rst named valve provided internally thereof, said cage having a port therein affording communication of the second port with said bore.

JOHN W. KELLY. 

